1. (Field of Technology)
The present invention generally relates to an automobile seat assembly and, more particularly, to a motor-driven seat slide mechanism for the adjustment in position of the automobile seat assembly in a direction generally parallel to the longitudinal sense of an automobile body structure.
2. (Description of the Prior Art)
Motorization of the seat slide mechanism in the field of automobile industry is not a recent development and is disclosed in numerous publications, for example, the Japanese Laid-open Utility Model Publications No. 60-89044, published June 18, 1985, No. 60-125230, published Aug. 23, 1985; and No. 60-127238.
According to the first mentioned two publications, there is disclosed a motor-driven seat slide mechanism which comprises a seat cushion mounted on an automobile floor panel through spaced apart, telescopically extendable guide rail structures; at least one screw shaft journalled at its opposite ends to one of the seat cushion and the floor panel so as to extend in a direction generally parallel to the longitudinal sense of the automobile body structure, specifically, the direction in which the seat assembly is desired to be adjusted; and an electrically powered drive motor having a drive shaft extending perpendicular to, and drivingly coupled with, the screw shaft through a motion translator rigidly mounted on the other of the seat cushion and the floor panel and operable to cause the screw shaft to move axially when the drive shaft of the motor is rotated. In this construction, a rotational force of the drive shaft of the drive motor when the latter is driven can be translated by the motion translator into a linear relative movement of the screw shaft accompanied by the displacement of the seat cushion in a direction generally parallel to the longitudinal sense of the automobile body structure.
The last mentioned publication also discloses a similar motor-driven seat slide mechanism. According to this publication, the screw shaft is rigidly connected at its opposite ends to the lower guide rail rigid with the floor panel of the automobile body structure so as to extend parallel to any one of the upper and lower guide rails. The slide mechanism disclosed therein makes use of a gear box including a worm gear, rigidly mounted on a drive shaft of the motor for movement together therewith, an externally and internally threaded worm wheel having an externally threaded region drivingly engaged with the worm gear and an internally threaded bore. This gear box is supported by the upper guide rail for movement therewith while the screw shaft drivingly extends through the internally threaded bore of the worm wheel so that the gear box can move in a direction axially of the screw shaft relative thereto.
According to the construction disclosed in the last mentioned publication, the upper guide rail, the gear box and the drive motor are all movable together with the seat cushion when the drive motor is operated. The drive of the drive motor is transmitted through the worm gear to the worm wheel which in turn drives the screw shaft to move the gear box, together with the upper guide rail and the drive motor, in a direction axially of the screw shaft relative to such screw shaft.
The prior art seat slide mechanisms hereinabove discussed are generally satisfactory in the sense that the position of the seat assembly relative to the steering wheel where the seat assembly in question is a front seat assembly, or relative to the front seat assembly where the seat assembly in question is a rear seat assembly, can be adjusted in a sophisticated manner.
However, it has been found that difficulties are involved in carrying out a repair when the drive motor breaks down. This will now be discussed in detail with particular reference to FIG. 8 of the accompanying drawings which schematically illustrates how the seat assembly 35 is installed on the floor panel 37 inside the automobile body structure according to the prior art. A pair of lower rail members 36 forming parts of the respective telescopically extendable guide rail structures and extending in a direction parallel to the longitudinal sense of the automobile body structure have their opposite ends secured to the floor panel 37 by means of respective front and rear fastening members 39 and 40 such as bolts. While upper guide rail members (not shown) also forming parts of the respective telescopically extendable guide rail structures and rigidly secured to the seat cushion are guided along the associated lower guide rail members 36, the seat assembly 35 as a whole can be displaced by the drive motor between front and rear positions as shown by the solid and phantom lines, respectively.
In this mounting of the seat assembly 35, in the event of the breakdown of the drive motor, the seat assembly 35 has to be removed from the floor panel 37 together with the telescopically extendable guide rail members so that a servicing man can have an access to the drive motor for the repair or replacement of the drive motor. The removal of the seat assembly 35 to provide the access to the drive motor is generally carried out by undoing ones of the front and rear fastening members 39, 40 and then the others of the front and rear fastening members 39, 40. However, where the drive motor is desired to be replaced or repaired after or while the seat assembly 35 has been moved to the front position as shown by the solid line, the access of a screw driver or any other tool 38 towards the front fastening members 39 tends to be hampered by a front edge portion of the seat cushion overhanging the front fastening members 39.
Similarly, where the drive motor is desired to be replaced or repaired after or while the seat assembly 35 has been moved to the rear position as shown by the phantom line, the access of a screw driver or any other tool 38 towards the rear fastening members 40 tends to be hampered by the seat back hingedly connected to a rear edge portion of the seat cushion.
In this way, the replacement of the repair of the motor which has become out of order is difficult to perform according to the prior art seat slide mechanism, requiring a time-consuming and laborious work to be done.
In my copending application Ser. No. 895,824, arrangement has been made to facilitate the access to the drive motor. According to my copending application, the upper guide rails are connected to the seat cushion through a seat frame structure including a cushion support frame for the support thereon of the seat cushion and a seat carrier frame mounted rigidly on the upper rails and to which the seat back is hingedly connected. The cushion support frame can be separated from the seat carrier frame and, therefore, when the cushion support frame is separated from the seat carrier frame together with the seat cushion, the drive motor and its associated parts can be exposed to the outside through the seat support carrier frame, thereby rendering the drive motor and its associated parts to be accessible to a servicing worker.